1. Field of the Invention
This invention relates to a method for visualizing higher-order structure of a transparent optical polymer molding suitable to visualize the higher-order structure such as a shear oriented layer, a spherulite and the like formed in thin disc-shaped transparent optical polymer moldings such as a compact disc (CD), a digital versatile disc (DVD) or so, and the transparent optical polymer molding in shapes of optical parts such as a lens, a prism or so made of high molecule substances in a wide region ranging from a microscopic level to a macroscopic level.
2. Description of the Prior Art
In recent years, the thin disc-shaped transparent optical polymer moldings such as a CD, a DVD and the like have been widely used as a high capacity recording medium instead of the conventional magnetic tape (DAT) and the magnetic disc (FD).
FIG. 10 is a vertical cross-sectional view illustrating the basic sectional structure of the transparent optical polymer molding of this kind (CD-ROM), a reading surface is shown on the upper side and a labelling surface is on the lower side in FIG. 10.
The transparent optical polymer molding (CD-ROM) 1 has a truly round shape with a diameter of 120 mm and a thickness of 1.2 mm (occasionally 0.6 mmxc3x972) typically, and is formed with a center hole 1a. The CD-ROM 1 is laminately formed with a polymer base (pit/land) 2, a reflecting layer (Aluminium layer) 3, a lacquer layer 4 and a printing layer 5 toward the labelling surface from the reading surface side.
In the transparent optical polymer molding of this kind, stable mouldability with high quality and high productivity are required in the injection moulding process, and it is required to meet, for example, the following demands that
a) the thickness of the product does not vary widely;
b) birefringence of the product is not large;
c) a large amount of warp does not appear in the product;
d) pattern stability of pits is secured; and
e) deformation or cracks are not produced in processes other than moulding, during the transportation, the strage and the application.
Therefore, it has been performed to enable advance examination of the higher-order structure such as the shear oriented layer or the spherulite produced in the transparent optical polymer moldings made of high molecule substances in order to carry out stable moulding of such the transparent optical polymer moldings with high quality, and several testing methods have been introduced, such as a polarized light transmission method, a photoelastic method, an interference method, a birefringence method, an FT-IR method, an ultrasonic method and so.
Additionally, some of these testing methods are described in Mechanical Engineer""s Handbook (JSME, Section A4, chapter 10, pp.152-154, New Edition, Second Printing, May 15, 1988).
However, the observation of the structure is mainly carried out in the microscopic region in the afore-mentioned conventional methods and there is a problem in that it is difficult to observe the whole structure of the transparent optical polymer moldings macroscopically in most cases. Accordingly, it becomes a subject to enable the observation of the higher-order structure of the transparent optical polymer moldings for the large sample such as the CD-ROM and the DVD in a wide region ranging from the microscopic level to the macroscopic level without destruction nor contact.
This invention is made in view of the aforementioned subject, and it is an object to provide a method for visualizing higher-order structure of a transparent optical polymer molding which is possible to observe the higher-order structure such as the shear oriented layer, the spherulite or so produced in the transparent optical polymer moldings made of high molecule substances in the wide region ranging from the microscopic level to the macroscopic level, is possible to know the influence on the mouldability (moulding trouble, residual strain, internal stress and so), the aging and/or degradation (relaxation phenomenon, thermal hysteresis, environmental degradation and so), the memory function or the like without damaging nor breaking the polymer materials in itself, and possible to estimate the physical and mechanical properties of the transparent optical polymer moldings.
The method for visualizing the higher-order structure of the transparent optical polymer molding according to this invention is characterized by comprising the steps of applying light with specific wavelength to the transparent optical polymer molding from an incident optical system, and visualizing light with specific wavelength selected among a reflected wave and/or a transmitted wave of the light applied to the transparent optical polymer molding from the incident optical system by an outgoing optical system.
The method according to an embodiment of this invention is characterized in that the transparent optical polymer molding is a product selected from the group consisting a disc, a flat lens, a prism and an optical filter formed from transparent resin such as polycarbonates, poly(ether sulfone), poly(ethylene terephthalate), polyolefine resins, acrylic resins, epoxy resins, and a mixture, alloy and composite material of these resins.
Further, the method according to another embodiment of this invention is characterized by using a light source which is possible to apply ultraviolet rays or near ultraviolet rays, such as a mercury lamp, an incandescent lamp, a black-light, a tungsten halogen lamp, a xenon lamp, an eximer UV lamp, a UV laser and so, as a light source of the incident optical system.
Furthermore, the method according to the other embodiment of this invention is characterized in that the incident optical system is provided with an incident-side filter to be passed through with light of which wavelength is not more than 400 nm.
The method according to the other embodiment of this invention is characterized by supporting the transparent optical polymer molding on a plane directly or multiple points, or in a suspended state.
The method according to the further embodiment of this invention is characterized in that the outgoing optical system is provided with an outgoing side-filter for selecting the light with the specific wavelength among the light reflected and/or transmitted from the transparent optical polymer molding, and the outgoing-side filter is passed through with light of which wavelength is in a range of 200 to 800 nm.
Furthermore, the method according to the other embodiment of this invention is characterized by providing an optical imaging system, an image pickup device, an image processing device and an image display device to the outgoing optical system.